Why does this watch have four hands?

The first time you look at a GMT watch, there’s a pretty obvious question. Why does this thing have four hands? Most watches give you three: hours, minutes, and seconds. A GMT adds one more. And unlike a lot of watch complications, this one is actually pretty easy to understand once you know what you’re looking at.

The Fourth Hand Has One Job

The extra hand on a GMT watch tracks another time zone. That’s it. The difference is that your normal hour hand goes around the dial twice every 24 hours, while the GMT hand only goes around once.

Instead of reading against the normal 12-hour markers, it points to a 24-hour scale, usually printed around the dial or on the bezel. So while your regular hour hand might be showing 3:00 in the afternoon, the GMT hand could be pointing to 20 on the bezel. That means it’s 8:00 PM in the second time zone you’re tracking.

Why 24 Hours?

There’s a practical reason for the 24-hour scale. If someone tells you it’s 7:00 somewhere else, that doesn’t necessarily tell you whether it’s 7:00 in the morning or 7:00 at night.

A 24-hour hand solves that. 7 means 7:00 AM. 19 means 7:00 PM. That becomes pretty useful when the time zone on the other end of the GMT hand is several hours away, especially if you’re trying to figure out whether calling someone would be perfectly reasonable or incredibly annoying.

The Movement Inside Out of Office

The JMR Out of Office uses Seiko’s 4R34 automatic GMT movement. The 4R34 belongs to the same general movement family as the workhorse automatics used in a lot of mechanical watches, but it adds that independently adjustable GMT hand.

It gives you automatic winding, manual winding, hacking seconds, a date display, and roughly 41 hours of power reserve. The 4R34 is what watch people usually call a caller GMT or office GMT. That means the GMT hand itself can be adjusted independently.

You set your normal hour hand to your local time, then set the GMT hand to whichever second time zone you want to follow.

Michigan Time. Nairobi Time.

One of my best friends lives in Nairobi, Kenya. I’m in Michigan. That means there are plenty of moments when I wonder what time it is over there before calling, texting, or sending him something that definitely does not need to wake him up.

Sure, my phone can tell me. Google can tell me. There are probably fifteen easier ways to figure it out. But having Nairobi sitting there on the fourth hand of my watch is more interesting.

My normal hands can stay on Michigan time. The GMT hand stays on Nairobi. One glance at the wrist and I know whether he’s probably working, eating dinner, sleeping, or wondering why somebody in Michigan is calling him at an unreasonable hour.

What Are All Those Numbers on the Bezel?

On a GMT watch, you’ll usually see a bezel marked from 1 through 24, or some variation of that scale. Those numbers are for the GMT hand.

If the fourth hand is pointing at 18, the second time zone is at 18:00 — or 6:00 PM. If it’s pointing at 6, it’s 6:00 AM.

Some GMT watches also use a rotating 24-hour bezel. That adds another trick. By rotating the bezel to account for the difference between two locations, you can use the same GMT hand to read a third time zone.

So technically, a watch with four hands can keep track of three places at once. Which is either incredibly useful or a good sign you need a vacation.

So Why Use a GMT at All?

There are obviously easier ways to know what time it is somewhere else. That’s true of almost everything a mechanical watch does. Your phone is more accurate. It changes time zones automatically. It has alarms, calendars, weather forecasts, maps, and whatever else we’ve decided our phones need to do this week.

Mechanical watches aren’t really about finding the easiest possible solution. They take something practical and turn it into something physical: gears, springs, hands, and a little machine sitting on your wrist.

A GMT takes the idea of another place and gives it its own hand. And sometimes that second time zone is more than a number. It might be where you’re headed next, where you just came home from, or where somebody important to you happens to be.

That’s what makes the fourth hand worth having.